This invention relates to data storage apparatus.
It is well known to provide data storage apparatus with some form of error detection and correction logic. For example, Hamming codes are typically able to detect double bit errors and to detect and correct single bit errors.
It is also well known to construct data storage apparatus from a number of memory devices such as random access memory chips. The chips may for example be mounted on a printed circuit board which provides input and output connections for data and for various control signals such as address bits, strobe signals and so on. The control signals are supplied to all the chips in parallel, and this usually requires the provision of suitable driver circuits for supplying the necessary drive current for fanning out each control signal to a number of chips.
One problem with such an arrangement is that if one of the driver circuits fails, it can cause several chips to give an incorrect output, leading to multiple errors which cannot be detected by the error detection logic.